1. Field of the Invention
This invention relates generally for drill bits and cutters used downhole in oil, gas or other type wells and particularly to cutters and drill bits for the removal of obstructions jammed in the casings of such wells.
2. Brief Description of the Prior Art
Well packers have, on occasion, been known to jam within the casing of oil and gas wells. When this occurs, there has been no practical means for removing the packer from the casing. Attempts to drill out or through the jammed packer with conventional drill bits have proved unsuccessful. Typically, the debris created by the drilling operation becomes jammed between the drill bit and the casing. The net result is that the drilling operation cannot be continued and often, the drill bit itself also becomes jammed within the well and is lost. When a packer becomes jammed in the casing of an oil or gas well and cannot be removed, the well is lost.
U.S. Pat. No. 2,663,546 to Kammerer is a conventional drill bit in terms of its operation and design. Kammerer apparently teaches a rotary drill bit having a center bore through which drilling fluid is pumped downward such that the fluid pushes the cuttings outward from the cutters washing them toward the well bore and then upward. The Kammerer drill bit would therefore be totally unsatisfactory for the removal of items such as well packers which become jammed within a well casing. The cuttings would become jammed between the drill bit and the casing preventing such cuttings from being flushed from the casing. This would result in a build-up of cuttings between the drill bit and the jammed packer. Ultimately, either the drill bit would seize cutting further into the jammed packer due to the build-up of cuttings or, the build-up of cuttings would cause the drill bit to seize or jam within the casing preventing further rotational movement.
U.S. Pat. No. 3,385,385 to Kucera et al teaches a roller drill bit for drilling through earth formations. The design of the cutters of Kucera et al do not direct the cuttings and debris inward nor does Kucera et al teach the flushing of the debris inward and up through the center bore of the drill bit. As such, the Kucera et al drill bit design is insufficient for the removal of well packers or other items which may become jammed within the casing of an oil or gas well.
U.S. Pat. No. 3,126,973 to Kiel teaches yet another rotary drill bit directed to drilling through earth formations. Kiel's drill bit is three conical cutters which have noncircular rows of teeth. The purpose of the noncircular rows of teeth is apparently to generate a vibratory action to increase penetration. The shaft is provided with a center bore through which fluid is pumped downward to flush debris outward from the drill bit. As such, the Kiel drill bit design is inadequate for the purpose of removing well packers or other items jammed within the casing of oil and gas wells.
U.S. Pat. No. 3,081,829 to Williams, Jr. teaches yet another drill bit design directed to boring holes into earth formations. As is the case with the prior art patents previously mentioned, Williams, Jr. does not teach cutters which direct the cuttings inward toward the center of the drill bit nor does it teach the flushing of such cuttings upward through the central bore of the bit. The same can be said for U.S. Pat. Nos. 2,094,856 to Smith et al and 2,533,260 to Woods. None would be adaptable for use in drilling out or through packers or other items jammed within the casing of an oil or gas well.